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Date:      Wed, 10 Jan 2007 20:38:18 -0500
From:      "Dak Ghatikachalam" <dghatikachalam@gmail.com>
To:        "Jay Chandler" <chandler@chapman.edu>, "Jeff MacDonald" <bignose@gmail.com>, "FreeBSD Questions" <freebsd-questions@freebsd.org>
Subject:   Re: Dell PE 1950 - Only seeing 3.2 gigs of ram
Message-ID:  <ba29b9b40701101738v29618198lb9a6999176091b6a@mail.gmail.com>
In-Reply-To: <20070110235022.GA54481@owl.midgard.homeip.net>
References:  <f17daf040701101347r4fa8f639u2421bff95a47f61@mail.gmail.com> <45A56BF3.40209@chapman.edu> <20070110235022.GA54481@owl.midgard.homeip.net>

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if you calculate the 32bit addressing capability

2^32 -1  = 4294967296 - 1   = 4GB -1 you could counter I/O space, IRQ space
for all the devices attached.

I have heard something like parity interleave(I may be misspelling that
word, but sounds close), you can knock off some more memory for this, and
something like memory hole,  you should knock off some more memory
for this.,  sometimes video card also steal  memory for acceleration, how
much of it all depends.

regards
Dak

On 1/10/07, Erik Trulsson <ertr1013@student.uu.se> wrote:
>
> On Wed, Jan 10, 2007 at 02:42:59PM -0800, Jay Chandler wrote:
> > Jeff MacDonald wrote:
> > >Hi,
> > >
> > >I put a fresh install of 6.1-RELEASE on a dell poweredge 1950 server.
> > >It's configured with 4 gigs of ram.
> > >
> > >However when I boot i get the following right before DMESG
> > >
> > >786432k above 4GB ignored
> > >
> > >Which is strange, but then dmesg shows this
> > >
> > >real memory  = 3489300480 (3327 MB)
> > >avail memory = 3414659072 (3256 MB)
> > >
> > >Soo I'm at a bit of a loss.
> > >
> > >Jeff.
> > >
> > Same platform, same error.  Anyone else have a clue for me?
> >
>
> Part of the 32-bit address space is reserved for various
> I/O-devices.  This means that a 32-bit OS will not be
> able to use all 4 GB of RAM but only a smaller amount (usually
> around 3.5 GB.)
>
> If you were to use a 64-bit OS it would probably be able to access
> all of the RAM if some of it is remapped to above the 4 GB
> line. (There is usually an option in the BIOS to do this remapping.)
>
>
> (This information is provided by most motherboard manufacturers
> and many computer manufacturers (including Dell) in some FAQ. )
>
>
>
> --
> <Insert your favourite quote here.>
> Erik Trulsson
> ertr1013@student.uu.se
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